Question

In ___ ___ ___ the third layer is offset exactly like the second.

A. Hexagonal close-packed
B. Body-centered cubic
C. Face-centered cubic
D. Cubic close-packed

Answer 1

The third layer in a cubic closest-packed structure is offset and aligns with the voids in the alternating layers, in a sequence of ABCABCABC.... This is the same as a face-centered cubic structure, making the correct answer D. Cubic close-packed.

Step-by-step explanation:

In the context of crystal structures, the third layer is offset exactly like the second in the cubic closest-packed (CCP) arrangement. This type of packing consists of three alternating layers in the sequence ABCABCABC..., where each atom in one layer is aligned with the voids in the adjacent layers, maximizing the density of the packing. The CCP structure is also referred to as a face-centered cubic (FCC) structure due to the arrangement of atoms on the faces of the cubic unit cell. Thus, the correct answer is D. Cubic close-packed.